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| Home > Publications database > Phasenfeldmodelle für Wachstumsprozesse in Multikomponenten- und Multiphasensystemen |
| Book/Report | FZJ-2019-03397 |
1997
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/22337
Report No.: Juel-3477
Abstract: The determination of the basic morphologies in the case of diffusion controlled growth is of physical and technological interest. In this thesis a phase field model for the description of the growth dynamics in a multi component - multi phase system is established. The dynamics of the fields are derived from an energy functional in a thermodynamically consistent way and the resulting equations are characterized by a minimal coupling at the interface. In the neighbourhood of unit undercooling the dynamics of growth can be described by a Kuramoto Sivashinsky equation. An analytical relation is derived between the phenomenological parameters of the phase field model and the physically relevant parameters of the sharp interface model (capillarity length, kinetic coefficient). For binary mixtures the doublon is identified as the basic morphology of the isotropic growth for pure energy tranfer as well as for coupled energy and mass transport. The influence of the additional matter transfer upon the length and time scales of the doublon is determined quantitatively. Furthermore the stability of the doublon is investigated respecting additive external noise. A triplet structure is identified as the three dimensional analogon to the two dimensional doublon. It consists of three asymmetrical finger-like structures that are rotated by 120 0 around a common axis.
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